1. Field of the Invention
The present invention relates to a novel aromatic compound or a salt thereof, and a pharmaceutical composition, particularly, an agent, for treating a kidney disease, containing said aromatic compound or a pharmaceutically acceptable salt thereof.
2. Description of the Related Art
There is now an increasing number of patients suffering from renal dysfunction. This is believed to be because a development of drugs appropriate to the treatment of kidney diseases has lagged behind with an increase in the number of senior citizens in the population or with changes in the environment. Therefore, drugs appropriate to the treatment of kidney diseases are urgently required.
More particularly, a method for treating lesions accompanying diseases, i.e., a nosotropic treatment, is mainly used for kidney diseases such as nephritis, diabetic nephropathy or renal failure. For example, an antihypertensive, diuretic or anti-inflammatory agent, or a dietary treatment, kinesitherapy or the like is used. Because kidney diseases are accompanied by hypertension, and because hypertension is believed to be one of the factors that aggravate kidney diseases, antihypertensive agents are often used. Of the antihypertensive agents, those that inhibit the production or function of angiotensin II are used in many cases. This is because angiotensin II is believed to be a factor aggravating kidney diseases as it raises the blood pressure and accelerates the growth of interstitial cells in the kidney, and an elimination of such a factor, insofar as possible, is believed to alleviate kidney diseases.
Specifically, the agents for inhibiting the enzyme which converts angiotensin I to angiotensin II, which raises the blood pressure, for example, the angiotensin converting enzyme inhibitor (such as enalapril or captoril) or the angiotensin II receptor antagonist (such as Dup753 or MK954), were developed as an antihypertensive agent for the treatment of kidney diseases.
In kidney diseases, the hypertension is an important symptom to be alleviated. A mere lowering of the blood pressure, however, is not sufficient. It is important to maintain an appropriate blood pressure, and thus, it is necessary to adjust the blood pressure by combining the kinds and doses of the antihypertensive agents in accordance with the symptoms. Nevertheless, a continuous treatment with a sufficient dose is required for the kidney diseases per se. Therefore, as long as a conventional antihypertensive agent is used, it is fundamentally impossible to appropriately adjust the blood pressure, and at the same time, to effectively cure a kidney disease by the antihypertensive agent alone. One such problem is, for example, an acute renal failure caused by the antihypertensive agent used.
Japanese Unexamined Patent Publication (Kokai) No. 8-48651 discloses compounds having novel properties, namely compounds providing a sufficiently effective alleviation of the renal dysfunction without any function to the blood pressure. These compounds are aromatic compounds which provide a sufficient effect in the alleviation of the renal dysfunction while the antagonism thereof to the angiotensin II receptor subtype 1 is one-hundredth (1/100) to one-thousandth (1/1000) or less that of the conventional antagonist having a standard activity as a antihypertensive agent.